Diagonal player movement is not normalized when holding two movement keys

Synopsis
The player can move faster than normal if you move diagonally by pressing two movement keys. It won't work if merely rotating your camera and pressing W.
The bug is most noticable when crouching, crawling or any other situation where the player is moving slowly. When crouching, pressing WD or WA results in aproximately 40% movement increase compared to only pressing W. The bug is still present when walking, sprinting, creative flying etc. however the speed increase from that is less than 5%.

To reproduce

• Enter a world and time how long it takes to cover a set distance while crouching.
• Ensure that you are only pressing one movement key during this time.
• Then, time how long it takes while pressing two movement keys and moving diagonally.

 Observed Results

• Moving diagonally by while crouching gives you a 40% speed boost

Expected Results

• This would not happen